Pyrophoric devices used in such a lighter generally comprise an abrasive striker wheel coacting with a flint which is pressed against the striker-wheel surface by a spring. The striker wheel, lying in a plane which includes the axis of the mouthpiece aperture and of the gas cartridge in line therewith, generates sparks designed to enter the gas flow issuing from the cartridge. It has already been proposed to use a sleeve situated near the periphery of the striker wheel or tongues carried by a flint-holding tube for the guidance of the sparks. With or without such guidance means, the sparks move generally transversely to the gas flow and, to a significant extent, pass through that flow at such a high speed that contact time is insufficient for ignition. Under adverse conditions, e.g. with low ambient temperatures or high humidity, such a lighter may fail to fire.